Agricultural feed bagging machines have been employed for several years to fill, pack, or bag silage or the like into elongate plastic bags. In these conventional bagging machines, silage or the like is supplied to the forward or intake end of the bagging machine and is fed to a rotor that conveys the silage into a tunnel on which the bag is positioned so that the bag is filled. As silage is loaded into the bag, the bagging machine moves away from the filled end of the bag due to the back pressure applied by the packed material against the machine. These machines included a pair of drums rotatably mounted on the bagging machine with a brake associated therewith for braking, or resisting, the rotation of the drum with a selected brake force. A cable or chain was wrapped around the drum and was released with rotation of the drum. A backstop structure was disposed at the closed end of the agricultural bag and was coupled to the bagging machine via the chains or cables to resist the movement of the bagging machine away from the filled end of the agricultural bag as silage was forced into the bag.
In more recent bagging machines, a density control means, which included a plurality of cables, was positioned in the flow of the silage material being bagged. In order to vary the density of the material in the machine, more or less cables would be employed based on the material being packed. For example, corn silage flows easily and would require more cables while alfalfa packs hard and would use less cables. Other arrangements are known in which the density of the material in the bag is controlled by a density control means positioned in the path of the material being bagged.
Control of the packing density during the bagging operation is important because a single bag may include material having different properties that packs differently. For example, a single bag may be several hundred feet long and may be packed with agricultural material, such as alfalfa, from all parts of a farm or region. The alfalfa is brought to the bagging machine in a number of separate loads, some of which may be wetter than others or some of which may include alfalfa cut longer than the alfalfa in other loads. The wet alfalfa or long alfalfa will pack more densely in a given bagging machine configuration than will dry or short alfalfa. Accordingly, a user may prefer to adjust the configuration of the density control apparatus in accordance with the material properties of the material being packed. Unfortunately, the extent and impact of the differences between the materials is rarely known until the material is packed into the bag and the packing density difference only evidences itself as loose packing or a bagging machine that is stuck due to the unexpectedly dense packing.
Previous bagging machines with adjustable density control apparatus allowed the user to control the packing density during operation based on their visual perception of the exterior of the bag and their sense for how hard the machine was working to pack additional material into the bag. Moreover, in many of the previous configurations, once a need to adjust the density control apparatus configuration was identified, it often took several feet of packing distance before the desired change was completed. For example, if the forward end of a cable loop is narrowed, the rearward end will trend narrower as it moves forward but it will not be as narrow as the forward end for at least several inches, if not several feet, of bagging machine movement.
Therefore, there are at least three areas where inaccuracy or delay can be introduced into the packing operation resulting in material being packed at a density other than the desired packing density. For example, the operator may be slow or inaccurate in observing changes in the packing density, the operator may be slow or inaccurate in executing the necessary commands or steps necessary to effect the change in the density control apparatus configuration, and/or the density control apparatus may introduce inherent delays between initiation of the configuration change and completion of the configuration change. Depending on the circumstances, that inaccuracy or delay may lead to undesirably loose packing for several inches or feet of the bag length or may cause the machine to become stalled due to the resistance force being greater than the available forward driving force. The loosely packed material wastes available storage space and may decrease the storage quality. A stalled machine interrupts the bagging operation and wastes many resources trying to free the machine from the packed bag and restarting the bagging operation. A bagging machine that provides for greater measurement of and control over the packing density is described herein.